Vauxhall Astra Owner's Manual page 100

Adjustable sensitivity of the rain
sensor
Turn the adjuster wheel to adjust the
sensitivity:
low = turn adjuster wheel
sensitivity downwards
high = turn adjuster wheel
sensitivity upwards
Keep the sensor free from dust, dirt
and ice.
Instruments and controls
Windscreen and headlight
washer
Pull lever. Washer fluid is sprayed
onto the windscreen and the wiper
wipes a few times.
If the headlights are on, washer fluid
is also sprayed onto the headlights,
provided that the lever is pulled
sufficiently long. Afterwards the
headlight washer system is
inoperable for 5 wash cycles or until
engine or headlights have been
switched off and on again.
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